There are various types of conventionally proposed manufacturing methods for obtaining accuracy of an inner diameter of a stator in manufacturing methods of a rotating electric machine having a plurality of split stator cores.
For example, in a manufacturing method of a rotating electric machine described in Japanese Patent Laying-Open No. 2001-218429, stress is uniformly applied to a stator core in a direction from an outer periphery toward an inner periphery to fix the core after locking slot open portions of stator teeth with equal pitch.
Japanese Patent Laying-Open No. 9-322493 describes a stator positioning jig for positioning a split stator main body for a rotating electric machine and a manufacturing method for manufacturing the split stator main body for the rotating electric machine by using the stator positioning jig.
The stator positioning jig includes a columnar inner diameter reference mandrel, stator positioning pins disposed annularly around the inner diameter reference mandrel for positioning respective unit cores, and a diameter reducing jig for pressing the unit cores mounted on the stator positioning pins toward the inner diameter reference mandrel. The stator positioning pins are inserted into stator positioning holes formed in the unit cores. Then, the diameter reducing jig is disposed to reduce a diameter of the respective unit cores. As a result, the respective unit cores hit against an outer periphery of the inner diameter reference mandrel to form the split stator main body for the rotating electric machine and with high roundness.
There is a stator manufactured by welding yoke portions of split cores as described in Japanese Patent Laying-Open No. 2006-304460.    Patent Document 1: Japanese Patent Laying-Open No. 2001-218429    Patent Document 2: Japanese Patent Laying-Open No. 9-322493    Patent Document 3: Japanese Patent Laying-Open No. 2006-304460